The shield is parted per fess. Above in a blue field is a silver demi-angel issuant, piping a German flute. The golden field beneath is divided by a blue bar wavy.
Meaning:
The angel with German flute appeared already in the local seal from 1953.
Source: §2(1) of Hauptsatzung of FernaKlaus-Michael Schneider, 15 Oct 2016

Presentation of Ferna

Ferna had 580 inhabitants in 2015 and covers 4.4 km². The municipality was first mentioned in 1062.
Klaus-Michael Schneider, 15 Oct 2016